While the world economy is expanding rapidly, some economists are concerned the U.S. economy could slow global growth as interest rates rise.

Overall economic growth may be at its fastest pace in 30 years, but some economic analysts remain worried.

Stephen Roach of Morgan Stanley in New York says the principal problem is the American consumer's reliance on debt to finance consumption. He says U.S. consumers are borrowing too heavily by using the value of their homes to back credit.

"Because they are spending increasingly, as asset dependent consumers extracting value from property, which by the way is clearly entering the stage of being a bubble, and going deeply into floating-rate debt to do that,” said Mr. Roach. “The American consumer is an accident waiting to happen."

Mr. Roach told a crowded opening session in Davos that the U.S. government is also spending and borrowing to heavily. He is doubtful that the Bush administration will make good on its pledge to cut the government budget deficit in half over the next four years.

The American budget and trade deficits were identified as the main reason why the dollar has declined significantly during the past two years.

Tokyo University Professor Takatoshi Ito suggests that as the Japanese economy expands the yen may continue its recent rise against the dollar. But Mr. Ito does not expect China to end its fixed currency link to the dollar. China, says Mr. Ito, will continue to register impressive economic growth.

"There is no stopping of this giant getting bigger and faster,” he noted. “And it reminds you, probably, of the Japanese economy in the 1950s and 1960s. The Japanese economy grew at a 10 percent annual rate for 20 years."

China registered nine percent economic growth in 2004 and that pace is expected to continue this year. The expert view is that even though world interest rates are going up, growth will persist in Asia, the Americas, Europe, and Africa.